I just got back from the prelude. 3 of us. 2 of them taking turns to beat the crap out of me. We tried your technique of me hanging on the back and yelling. It worked ok until a gap opened up (actually it happened quite often towards the end) and they charged off missing a turn and i couldnt yell loud enough. Have you ever tried yelling with your lungs pushing up into your throat?

excellent ride. I feel great. I need to ride this hard more often.